Decreasing the dimensions of electronic devices and increasing the level of their integration are two major trends in current electronic device manufacturing. As a result of these trends, the density of elements forming a semiconductor device continuously increases. The shrinkage of the semiconductor devices involves performing the routine fabrication of the semiconductor device elements on the submicron level.
Typically, an electronic device is fabricated on a wafer using many layers of films. Generally, layers of various semiconducting, conducting and insulating materials are used to form the integrated circuits. These layers may be doped, deposited and etched to form electronic devices. A layer of the electronic device may be fabricated using a mask that dictates the pattern of the layer.
Advanced patterning technologies are developed for photolithography to enhance the feature density. An example of the advanced patterning technologies is a multiple patterning process, where a lithography process is enhanced to increase the existing number of features. Typically, in the double patterning process spacers are formed on the sidewalls of a pre-patterned feature. The original pre-patterned feature is then removed. Because there are two spacers left for every feature, the feature density is doubled.
A carbon film is typically used as a sacrifice layer in the semiconductor process flow. Typically, the carbon film is deposited on the substrate by a blanket deposition technique. The carbon film is then etched to produce a pattern to etch the underlying substrate. The patterned carbon film can be used as a hard mask to transfer a pattern to the underlying substrate.
Current carbon film deposition techniques, however, have poor trench and via fill capability. Typically, the carbon film deposition techniques do not fill the bottom of the deep trench. The current carbon film deposition techniques result in clogging and voids in high aspect ratio trenches and vias. Additionally, current carbon film deposition techniques do not have deposition selectivity to silicon oxide. These shortcomings limit the use of the carbon films for many applications.